Biological molecules official content key terms

Monomer

A monomer is a small, basic molecular unit that can join together with other monomers to form larger molecules, such as proteins from amino acids.

Peptide bond

A peptide bond is a covalent bond that links amino acids together in a protein, formed through a condensation reaction.

Condensation reaction

A chemical reaction where two molecules combine to form a larger molecule, with the loss of a small molecule, often water.

Amino acid

Organic compounds that serve as the building blocks of proteins, containing an amino group, a carboxyl group, and a side chain.

Denaturation

The process by which a protein loses its native shape due to the disruption of non-covalent interactions.

Active site

The region of an enzyme where substrate molecules bind and undergo a chemical reaction.

Tertiary structure

The overall 3D shape of a protein formed by the folding of its polypeptide chain.

Secondary structure

Local folded structures that form within a protein due to hydrogen bonding, such as alpha helices and beta sheets.

Proteins

Large biomolecules composed of one or more long chains of amino acid residues.

Biuret reagent

A solution containing copper(II) sulfate used to test for proteins.

Enzyme

A protein that acts as a catalyst to accelerate a biochemical reaction.

Catalyst

A substance that increases the rate of a chemical reaction without being consumed in the process.

Enzyme

A biological catalyst that speeds up chemical reactions in living organisms by lowering the activation energy.

Substrate

The reactant molecule upon which an enzyme acts.

Enzyme concentration

The amount of enzyme present in a reaction, which can affect the rate of reaction if substrate is in excess.

Substrate saturation

A condition where all active sites of an enzyme are occupied by substrate, leading to a maximum rate of reaction.

Enzyme

A biological catalyst that speeds up chemical reactions in living organisms by lowering the activation energy.

Active Site

The specific region of an enzyme where substrate molecules bind and undergo a chemical reaction.

Catalyst

A substance that increases the rate of a chemical reaction without undergoing any permanent chemical change.

Substrate

The reactant molecule upon which an enzyme acts.

Deoxyribonucleotide

A nucleotide that contains deoxyribose sugar, a phosphate group, and one of four nitrogenous bases (adenine, thymine, cytosine, or guanine).

Ribonucleotide

A nucleotide that contains ribose sugar, a phosphate group, and one of four nitrogenous bases (adenine, uracil, cytosine, or guanine).

Nucleotide

The basic building block of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogenous base.

Deoxyribose

A five-carbon sugar that is a component of DNA nucleotides.

Phosphodiester bond

A type of covalent bond that connects the phosphate group of one nucleotide to the sugar of another nucleotide in a nucleic acid.

DNA polymerase

An enzyme that synthesizes DNA molecules from nucleotides, playing a crucial role in DNA replication by forming phosphodiester bonds.

Double helix

The structure formed by double-stranded DNA, resembling a twisted ladder, where the sides are made of sugar and phosphate, and the rungs are formed by base pairs.

Complementary base pairing

The specific pairing of nitrogenous bases in DNA, where adenine pairs with thymine and cytosine pairs with guanine, allowing for accurate replication and transcription.

Base-pairing

The specific hydrogen bonding between nitrogenous bases in DNA, where adenine pairs with thymine and cytosine pairs with guanine.

Chargaff's rules

The observation that in double-stranded DNA, the amount of adenine equals thymine and the amount of cytosine equals guanine.